	TTYIN,			/Read from TTY
	/			  returns character in ac
	TTYILP,	
		KSF		/ await input ready
		JMP	TTYILP
		KRB		/ read character
		JMP I	TTYIN

	TTYOUT,	.-.		/Write to TTY
	/			  given character in ac
	TTYOLP,	TSF		/ await input ready
		JMP	TTYOLP
		TLS		/ write character
		JMP I	TTYOUT
